1. Field of the Invention
The invention relates to metallic glasses having high permeability, low magnetostriction, low ac core loss and high thermal stability.
2. Description of the Prior Art
As is known, metallic glasses are metastable materials lacking any long range order. X-ray diffraction scans of glassy metal alloys show only a diffuse halo similar to that observed for inorganic oxide glasses.
Metallic glasses (amorphous metal alloys) have been disclosed in U.S. Pat. No. 3,856,513, issued Dec. 24, 1974 to H. S. Chen et al. These alloys include compositions having the formula M.sub.a Y.sub.b Z.sub.c, where M is a metal selected from the group consisting of iron, nickel, cobalt, vanadium and chromium, Y is an element selected from the group consisting of phosphorus, boron and carbon and Z is an element selected from the group consisting of aluminum, silicon, tin, germanium, indium, antimony and beryllium, "a" ranges from about 60 to 90 atom percent, "b" ranges from about 10 to 30 atom percent and "c" ranges from about 0.1 to 15 atom percent. Also disclosed are metallic glassy wires having the formula T.sub.i X.sub.j, where T is at least one transition metal and X is an element selected from the group consisting of phosphorus, boron, carbon, aluminum, silicon, tin, germanium, indium, beryllium and antimony, "i" ranges from about 70 to 87 atom percent and "j" ranges from about 13 to 30 atom percent. Such materials are conveniently prepared by rapid quenching from the melt using processing techniques that are now well-known in the art.
Metallic glasses are also disclosed in application Ser. No. 590,532, filed June 26, 1975. These glassy alloys include compositions having the formula M.sub.a M'.sub.b Cr.sub.c M".sub.d B.sub.e, where M is one iron group element (iron, cobalt and nickel) M' is at least one of the two remaining iron group elements, M" is at least one element of vanadium, manganese, molybdenum, tungsten, niobium and tantalum, B is boron, "a" ranges from about 40 to 85 atom percent, "b" ranges from 0 to about 45 atom percent, "c" and "d" both range from 0 to about 20 atom percent and "e" ranges from about 15 to 25 atom percent, with the proviso that "b", "c" and "d" cannot be zero simultaneously. Such glassy alloys are disclosed as having an unexpected combination of improved ultimate tensile strength, improved hardness and improved thermal stability.
These disclosures also mention unusual or unique magnetic properties for many metallic glasses which fall within the scope of the broad claims. However, metallic glasses possessing a combination of higher permeability, lower magnetostriction, lower core loss and higher thermal stability than prior art metallic glasses are required for specific applications such as tape recorder heads, relay cores, transformers and the like.